1: such sort of splotches definitely happens with load of relatively tiny portals on the way of light; solution is to use detail brushes
2: can't it be the effect of grates with alphashadow or lightfiler?
You also may try to remove switches from Final preset one by one to figure out which one is responsible for splotches

(08-01-2018, 09:18 PM)Garux Wrote: 1: such sort of splotches definitely happens with load of relatively tiny portals on the way of light; solution is to use detail brushes
2: can't it be the effect of grates with alphashadow or lightfiler?
You also may try to remove switches from Final preset one by one to figure out which one is responsible for splotches

Looks like it's definitely the glass / mesh (removing them makes the problem go away), though switching alpha shadow off doesn't appear to help much.

I'm currently debating whether to figure this out further or take this as my cue to redo the area (I wasn't completely happy with it, so this may be an opportunity to replace the visuals with something else).